1. Field of the Invention
The present invention relates to a battery holder for a disc-like button-type battery such as a lithium battery.
2. Description of the Related Art
Referring to FIGS. 6 to 11, conventional type battery holder for a button-type battery will be described below.
A reference number 11 denotes a button-type battery such as a lithium battery, 12a denotes one surface of it, 12b denotes a circumferential face, 12c denotes the other surface, the other surface 12c and the circumferential face 12b are integrated by a metal plate and normally function as a positive electrode. A metal plate forming one surface 12a is insulated from the positive electrode and functions as a negative electrode.
A reference number 13 denotes a battery holder as a whole and the battery holder is composed of a holder body 14, a first terminal 15 and a second terminal 16.
The first terminal 15 is made of conductive and elastic material and as clear from FIG. 10, is composed of a contact part 17, a protruded piece 18 and a fitting piece 19 folded downward at the back of the contact part 17. A bent piece 19a is further formed on the fitting piece 19. Needless to say, each part and each piece are integrated.
The second terminal 16 is similarly made of conductive and elastic material, as clear from FIG. 11, is composed of a main plate part 20, folded pieces 21a and 21b, an extended piece 22 protruded in a direction perpendicular to the longitudinal direction of the main plate part 20 and a pair of contact pieces 23a and 23b acquired by tilting them from the surface of the main plate part 20 and these contact pieces 23a and 23b are actually mechanically and electrically touched to one surface 12a of the battery 11.
The end of the extended piece 22 is folded downward, a protruded piece 22a is formed and the width of each of the folded pieces 21a and 21b is formed so that it is narrower than that of the main plate part 20. For the second terminal 16, each part and each piece are also integrated.
The holder body 14 is formed by insulating material such as synthetic resin by so-called molding, is provided with a plate part 25 corresponding to one surface 12a of the battery 11 and a circumferential part 26 corresponding to the circumferential face 12b of the battery 11, a part corresponding to the other surface 12c of the battery 11 is open, a so-called opening 27 is formed, a part of the circumferential part 26 is cut out and a cut-out part 28 is formed. The cut-out part 28 is formed so that it has relatively large area.
A through hole 29 is formed on the reverse side to the cut-out part 28 of the circumferential part 26, a through hole 30 is formed through the plate part 25 and further, fitting holes 31a and 31b are respectively formed in the right and left parts of the circumferential part 26 (parts located in a direction perpendicular to a line connecting the cut-out part 28 and the through hole 29). The width of each of the fitting holes 31a and 31b is set so that the width is slightly larger than that of each of the folded pieces 21a and 21b of the second terminal 16.
Front flanges 33a and 33b and rear flanges 34a and 34b which block a part of the opening 27 are formed on both sides of the cut-out part 28 and on the reverse side of the cut-out part 28 on the circumferential part 26 of the holder body 14.
The first terminal 15 is arranged in the rear (on the reverse side to the cut-out part 28) of the holder body 14 in a state in which the protruded piece 18 is inserted into the through hole 30 of the plate part 25 and the fitting piece 19 is inserted into the through hole 29 of the circumferential part 26, however, in a state in which the battery 11 is not housed (an unused state) the curved contact part 17 is also arranged between the plate part 25 and the rear flanges 34a and 34b. 
Therefore, when the first terminal 15 is once arranged in a predetermined position, it is never uncoupled from the holder body 14. In this state, the bent piece 19a of the fitting piece 19 is fitted to a part of the circumferential part 26.
The second terminal 16 is attached to the holder body 14 by fitting the folded pieces 21a and 21b (particularly their upper ends) on both sides into the fitting holes 31a and 31b of the circumferential part 26. At this time, as the width of the main plate part 20 of the second terminal 16 is larger than that of the fitting holes 31a and 31b, the second terminal 16 never falls outside the holder body 14 through the fitting hole 31a or 31b. 
According to a such configuration, as shown in FIG. 7, when the battery 11 is inserted by pressing it on the first terminal 15 from the side of the cut-out part 28 through the opening 27 of the battery holder 13, the contact part 17 of the first terminal 15 is backed by this pressure and the end on the side of the cut-out part 28 of the battery 11 is moved from the front flanges 33a and 33b to a back position.
At this time, when the battery 11 is pressed on the inside of the battery holder 13, it is lowered against spring by the contact pieces 23a and 23b of the second terminal 16, when the battery becomes lower than the front flanges 33a and 33b, it is pressed forward, that is, in a direction of the cut-out part 28 by the spring of the first terminal 15 and the circumferential face on the side of the front end of the battery 11 is pressed on the inner face of the circumferential part 26 in the vicinity of both sides of the cut-out part 28 of the battery holder 13.
The other surface 12c of the housed battery 11 is pressed by the front flanges 33a and 33b and the rear flanges 34a and 34b of the battery holder 13, hereby, the battery 1 can be prevented from falling outside via the opening 27 and is stably and securely secured in the battery holder 13. These flanges 33a, 33b, 34a and 34b function as a preventive part. Voltage can be acquired between the first terminal 15 and the second terminal 16.
When the battery 11 housed in the battery holder 13 as described above is strongly pushed in a direction of the first terminal 15 with a fingertip put on the cut-out part 28 of the battery holder 13, it can be separated from the front flanges 33a and 33b of the battery holder 13, that is, from a presser, that is, the battery 11 can be lifted outside the battery holder 13 from the front end of the battery 11, as a result, it is picked up with fingertips and can be extracted.
The conventional type battery holder for a button-type battery has a problem that as the battery 11 is extracted from the cut-out part 28 with a fingertip put on the cut-out part 28 provided to the battery holder 13 as described above when the battery 11 housed in the battery holder 13 is extracted and the battery 11 is not held in the cut-out part 28, the battery 11 sometimes falls out of the battery holder 13 easily.